Could not find or load main a class in Java

Question

i have the following project structure:

JavaTest
    Main
        Main.java
    Test
        Test.java

Main.java:

package Main;
import Test.*;
public class Main {
    public static void main(String[] args) {
    }
}

Test.java:

package Test;
public class Test {
}

I compile them with the following commands:

D:\Development\Workspace\JavaTest>javac Main\Main.java

D:\Development\Workspace\JavaTest>javac Test\Test.java

The class files are put like this:

JavaTest
    Main
        Main.java
        Main.class
    Test
        Test.java
        Test.class

I'm trying to run it with the following command:

D:\Development\Workspace\JavaTest>java -cp D:\Development\Workspace\JavaTest\Main;D:\Development\Workspace\JavaTest\Test Main

The error i'm getting is:

Error: Could not find or load main class Main
Caused by: java.lang.NoClassDefFoundError: Main/Main (wrong name: Main)

Does this help: https://stackoverflow.com/questions/7509295/noclassdeffounderror-wrong-name — Oozeerally, Feb 01 '20 at 17:03

score 3 · Accepted Answer · answered Feb 01 '20 at 17:06

add the package to your main class and set the classpath to the base directory

D:\Development\Workspace\JavaTest>java -cp D:\Development\Workspace\JavaTest Main.Main

I'd recommend you stick to Java conventions and use only lowercase names in your package. And you don't need the Test path to run your class

score 1 · Answer 2 · answered Feb 01 '20 at 17:13

Do it as follows:

javac -d . Main/Main.java
java Main.Main

Notes:

The current directory is represented by a .
I recommend you follow the Java naming convention. As per the naming convention, the name of your package should be main. Check https://www.oracle.com/technetwork/java/codeconventions-135099.html for more details.
Use the command, javac -help to know more about the options available with javac.

2 Answers2